BRIGHTNESS ENHANCING FILM AND FILM BASED DIFFUSER FOR IMPROVED ILLUMINATION UNIFORMITY OF DISPLAYS

摘要

An optical device has a first film that has a first side and a second side. When illuminated by light at the first side, the first film is characterized by a first fraction of broadly diffused transmitted light and a second fraction of narrowly diffused transmitted light. A second film is disposed to the second side of the first film. The second film has at least one free surface that diverts light. In some embodiments, the first film has a diffuse scattering optical density between 0.5 and 3. The device finds use in spreading and making light uniform in a backlight in a display such as a liquid crystal display.